1. Field of the Invention
This invention relates to the field of electrical connectors adapted to be used in a telephone transmission system having multiple contacts.
The direction of present day telephone technology is towards the "modular apparatus" concept, particularly that portion of telephone technology that deals with the telephone system between trunk telephone line and the individual subscriber's handset, more particularly telephone handsets, cords, wall jacks or receptacles. Most equipment of this nature can be simply and easily plugged into one another to form electrical connection with a telephone transmission pair and can be easily removed from such a connection and transported into another location and re-connected to the same or another telephone transmission pair, all without the aid of a skilled telephone repairman. Examples of so-called modular apparatus (jacks and plugs) of this nature are described in U.S. Pat. Nos. 3,990,764; 3,850,497 and 4,188,082; the disclosure of which are hereby incorporated by reference as if they were faithfully reproduced.
Plugs and jacks as presently used in modern day telephone "modular apparatus" arrangements usually have a plurality of contacts, which in most cases are gold plated in order to enhance the electrical path made by this contact. Such contacts, if not protected from the outside environment, have a tendency to become coated with grease, grime, dust and other particles, which increase the attenuation of the circuit and reduce the effectiveness of the plug and jack arrangement. This problem is identified and discussed in U.S. Pat. No. 4,188,082 and, in a general sense, this invention addresses the same problem.
2. Description of Prior Art
The most relevant prior art relating to the telephone wall jack of the instant invention known to the applicants' is a modular jack cover manufactured by Western Electric Company and Suttle Apparatus Corporation of Lawrenceville, Ill., both having a product designation of 625S. This jack cover is basically a three piece composit, comprising a jack housing, a jack and a gate or cover. The jack housing is rectilinear in shape, the jack being exposed on one surface thereof. The jack housing cover is rotatably affixed to a portion of the surface of the jack housing cover in a biased position covering the exposed jack. Exposure of the jack cavity is accomplished by rotating the cover.
The disclosed invention, like that of the relevant above described prior art, facilitates the connection of a telephone handset to the transmission pair of a telephone system, and is usually mounted flush on the lower third of a wall. Connection of a telephone handset to the telephone transmission pair is achieved in a manner well known in the art, e.g., by means of drop wire from the transmission pair to a building, inside wire from the inside wire to a jack and a line cord from the jack to the telephone handset. A line cord is a cord containing a transmission pair and terminated on at least one end by a modular connector, sometimes called a plug; usually both ends are terminated by a modular connector. The jack portion is a cavity into which the modular connector is slidably insertable to make an electrical connection with the telephone transmission pair to which the other terminal end of the line cord is connected to the telephone handset in a like manner.
Most surface mounted telephone jacks of the type to which this invention relates are designed to be installed at the bottom third of the wall, i.e., within the first three feet above the floor. Because such wall jacks are exposed, i.e., open receptacles or cavities, it has been found that dust, grime, mop water, grease, along with condensation, tend to collect in the connector cavity, all of which increase the attenuation of the connection, thereby producing undesirable transmission results. Furthermore, a jack cavity saturated with water will smolder and possibly catch on fire when ringing voltage is applied to a connector inserted in it. Consequently, anything that can be done to close off the wall jack cavity from the elements of the room is a step forward.
Because such wall jacks are usually installed in the bottom third of a wall and because such jacks are in communication with the interior of the wall, if left uncovered, they have a tendency to experience a "chimney effect." This chimney effect is referred to in U.S. Pat. No. 4,188,082 and is understood to be convection air currents moving from a usually warm room into the connector cavity and thereafter into a colder wall cavity behind the telephone jack. These currents of air carry dust particles, water vapor and the like and tend to move from the room into the jack cavity, over the electrical contacts and wiring used in the jack housing to make electrical connections and out the back side of the housing into the wall cavity itself. This so-called "chimney effect" not only has a tendency to bring into the connector cavity and in contact with electrical components undesirable particulate matter such as dust, dirt, grease and the like but also tends to deposit water condensate on the electrical components in the connector cavity, because of the temperature change of the air from a warm room temperature to a colder temperature existing in the wall cavity itself. It is towards this solution of the above identified problems that this invention is directed.